A music apparatus utilizes a tone generator including a plurality of tone generating elements to generate a plurality of music tones arranged in a set of performance parts of a music piece based on sequence data. An assigning section assigns the plurality of tone generating elements to the set of the performance parts. A sequencer processes the sequence data to sequentially provide parameters for use in the tone generating elements. A register is divided into a first area for storing first parameters to be applied individually by each of two or more tone generating elements and a second area for storing a second parameter to be applied commonly by two or more tone generating elements. Each tone generating element uses both of the stored first parameter and second parameter corresponding to the tone generating element.